It's not just the domestic market which companies are aiming at but also the enterprise/corporate market.
Microsoft is pushing the Azure product hard (running all your servers in the Microsoft cloud). Google Apps is also classified as SaaS and sales people in general are touting 'The cloud' as the magical silver bullet which will fix all your server woahs. Unfortunately, a lot of management, especially management which is not very technical swallow it all hook, line and sinker.
While 'The cloud' does have it's place, it is not the magical solution being pushed. it should be used to enhance your environment and not replace it. If your solution does not work on your own servers, it will not mystically start working when moved to the cloud.
The other thing which comes into play which has mentioned here is where your data is being stored. The problem for non-American companies is that even if the data is not stored on American property, if the company is American, the data still falls under the patriot act ie. the government can access it anyway.
As for the domestic side, there are a number of reasons Microsoft and others want you to use SaaS; They control it, you rent it, it's cheaper for them etc.
It's all about horse for courses and working out what you really need and with the corporate world, if you have th einhouse skills to manage it yourself or not. the other problem is, a large number of people don't really grasp the concept of what the cloud is. Just because it is being hosted externally does not make it a cloud solution.
I have seen things which make sense to put into the cloud but I have seen a lot of things which don't and have been.